This section is from the book "Nature's Garden", by Neltje Blanchan. Also available from Amazon: Nature's Garden; An Aid To Knowledge Of Our Wild Flowers And Their Insect Visitors.
Flowers - Very small, white, slender pedicelled, in terminal and lateral racemes. Calyx 2-parted, hairy; 2 petals, 2 alternate stamens. Stem: 1 to 2 ft. high, slender, branching, swollen at nodes. Leaves: Opposite, tapering to a point, distantly toothed, 2 to 4 in. long, slender petioled. Fruit: Pear-shaped, 2-celled, densely covered with stiff, hooked hairs.
Preferred Habitat - Woods; shady roadsides.
Flowering Season - June - August.
Distribution - Nova Scotia to Georgia, westward to Nebraska. Europe and Asia.
Why Circe, the enchantress, skilled in the use of poisonous herbs, should have had her name applied to this innocent and insignificant looking little plant is not now obvious; neither is the title of nightshade any more appropriate.
Each tiny flower having a hairy calyx, that acts as a stockade against ants and other such crawling pilferers, we suspect there are abundant sweets secreted in the fleshy ring at the base of the styles for the benefit of the numerous flies seen hovering about. Among other visitors, watch the common house-fly alighting on the knobby stigma, a most convenient landing place, where he leaves some pollen carried on his underside from other nightshade blossoms. In clasping the bases of the two pliable stamens, his only available supports as he sucks, he will surely get well dusted again, that he may fertilize the next blossom he flies to for refreshment. The nightshade's little pear-shaped seed-vessels, armed with hooked bristles by which they steal a ride on any passing petticoat or trouser-leg, reveal at a glance how this plant has contrived to travel around the globe.
A smaller, weaker species (Circaea alpina), found in cool, moist woods, chiefly north, has thin, shining leaves and soft, hooked hairs on its vagabond seeds. Less dependence seems to be placed on these ineffective hooks to help perpetuate the plant than on the tiny pink bulblets growing at the end of an exceedingly slender thread sent out by the parent roots.